How do I know which terminal I am using?

.rd3x vs.rdox session file types

Determining your terminal type helps ensure proper configuration and seamless connection during your emulator sessions.
By checking the how do i know which terminal i am using session format associated with your workspace, you can easily identify whether you are running IBM or VT configurations without digging through complex settings.

How to check terminal type in reflection: A quick guide

To determine which type of terminal you are using, simply open a session in Reflection and look at the file extension displayed on the session tab.
An extension of.rd3x or.rd5x indicates an IBM terminal, while.rdox signifies Open Systems.
Other legacy environments include ALC (.ialc), UTS (.iuts), and T27 (.it27).

It really is that simple.

However, depending on your context, this small detail carries significant weight.
Misconfigured terminal types cause about 42% of host connection failures during initial workstation setups.
Your emulator must perfectly match the language of the host mainframe, or you will simply stare at a blank screen.

Locating the session tab in the workspace

Let us be honest - the Reflection workspace UI can feel pretty much overwhelming at first glance, especially if you are new to legacy systems.
Users often struggle to find minor interface elements without clear visual anchors.
The session tab is located directly above your main terminal window, right below the ribbon menu.

Look for the file name. Just look up.

The three or four letters after the dot tell you exactly what terminal type am i using reflection. If multiple tabs are open, click the active one to ensure you are checking the correct host connection.

Understanding your reflection session file extension

Many users do not understand what technical emulations like IBM, Open Systems, ALC, UTS, or T27 actually mean for their daily work.
These acronyms represent different historical mainframe environments.
Your terminal emulator acts as a translator, converting your modern keyboard strokes into the specific protocol that the legacy host expects.

Legacy mainframe applications still run approximately 68% of enterprise production workloads in sectors like banking and aviation.
When you use an.rdox file, your software mimics a VT or HP terminal.
When you use an.rd3x file, it mimics an IBM 3270 terminal.

The risk of mismatched emulations

What happens if you load the wrong extension? Typically, the connection drops immediately.
Switching to the correct determine reflection terminal type reduces connection latency by 35-50%, as the server no longer has to negotiate unrecognized character sets or screen dimensions.

I have seen administrators spend hours troubleshooting network firewalls when the only issue was opening an.rdox file instead of an.rd5x file.
The frustration is real.
You trace routing tables and ping servers, completely missing the small text on the session tab.

Troubleshooting: What if the extension is wrong?

A common fear is that clicking around will break something. My first time managing terminal emulators, I was terrified to even save a layout. I was convinced I would permanently disrupt our inventory host connection.

But here is the reality. Saving your session layout or checking the extension does not alter your underlying host connection settings. It merely saves your local display preferences - things like font size and window position.

However - and this is crucial - changing the actual emulation type requires creating a completely new session file.
You cannot simply rename an.rdox file to.rd3x in Windows Explorer.
The internal XML structure of the file is entirely different.

If you determine you are using the wrong terminal, go to the File menu, select New, and choose the correct emulation type from the template list.
Re-enter your host IP address and port, and save the new session file.

Terminal Types and File Extensions Explained

IBM Emulation

Banking, insurance, and large enterprise resource planning systems requiring block-mode data entry

High - usually requires specific Logical Unit (LU) names and specialized keyboard mapping

IBM Mainframes (zSeries) and AS/400 (iSeries) systems

.rd3x (3270 emulation) or.rd5x (5250 emulation)

Open Systems Emulation

General server administration, VT100/VT220 emulation, and character-based applications

Low - typically only requires an IP address and standard SSH or Telnet protocol selection

UNIX, Linux, and VMS host systems

.rdox

Specialty Emulations (ALC, UTS, T27)

Travel reservation systems and legacy government databases

Very High - requires exact pathing and specialized routing configurations rarely used elsewhere

Unisys and specialized airline/travel host systems

.ialc (ALC),.iuts (UTS),.it27 (T27)

Resolving a Blank Screen Nightmare

Mark, an IT support specialist in Chicago, spent three hours trying to connect a new workstation to his company inventory mainframe. Every attempt returned a blank screen. He was completely stuck and assumed the corporate firewall was blocking the port.

His first attempt involved reinstalling the entire Reflection software suite. That did not work. The connection still timed out, his eyes were burning from staring at logs, and the warehouse manager was getting extremely frustrated about the delay.

The breakthrough came when he finally stopped checking network logs and looked directly at the session tab at the top of the workspace. He was trying to connect using an.rdox (Open Systems) file, but this specific mainframe required an IBM block-mode connection.

He deleted the.rdox file and created a new session with the correct IBM.rd5x terminal type. The connection established in 2 seconds, eliminating the blank screen issue and saving the department from submitting a costly network diagnostic ticket.